class Cl1 {
	public void f() {
		System.out.format("Cl1: f\n");
	}
}

class Cl2 extends Cl1 {
	public void f() {
		System.out.format("Cl2: f\n");
	}

	public void g() {
		System.out.format("Cl2: g\n");
	}
}

public class Lrn002 {
	public static void main(String[] args) {
		Cl2 c2 = new Cl2();
		Cl1 c1 = (Cl1) c2;
		Cl1 c11 = new Cl1();
		c2.f();
		c2.g();
		c1.f();
		//c1.g();
		c11.f();
	}
}
